How to validate GUID is a GUID

Question

How to determine if a string contains a GUID vs just a string of numbers   will a GUID always contain at least 1 alpha character

User · Answer

There is no guarantee that a GUID contains alpha characters. FFFFFFFF-FFFF-FFFF-FFFF-FFFFFFFFFFFF is a valid GUID so is 00000000-0000-0000-0000-000000000000 and anything in between.

If you are using .NET 4.0, you can use the answer above for the Guid.Parse and Guid.TryParse. Otherwise, you can do something like this:

public static bool TryParseGuid(string guidString, out Guid guid)
{
    if (guidString == null) throw new ArgumentNullException("guidString");
    try
    {
        guid = new Guid(guidString);
        return true;
    }
    catch (FormatException)
    {
        guid = default(Guid);
        return false;
    }
}

User · Answer

Use GUID constructor standard functionality  Public Function IsValid pString As String  As Boolean      Try         Dim mGuid As New Guid pString      Catch ex As Exception         Return False     End Try     Return True  End Function

User · Answer

When I m just testing a string to see if it is a GUID  I don t really want to create a Guid object that I don t need   So     public static class GuidEx       public static bool IsGuid string value                Guid x          return Guid TryParse value  out x             And here s how you use it   string testMe    not a guid   if  GuidEx IsGuid testMe

User · Answer

Will return the Guid if it is valid Guid  else it will return Guid Empty  if   Guid TryParse yourGuidString  out yourGuid              yourGuid  Guid Empty

User · Answer

Based on the accepted answer I created an Extension method as follows   public static Guid ToGuid this string aString        Guid newGuid       if  string IsNullOrWhiteSpace aString                 return MagicNumbers defaultGuid             if  Guid TryParse aString  out newGuid                 return newGuid             return MagicNumbers defaultGuid      Where  MagicNumbers defaultGuid  is just  an empty  all zero Guid  00000000-0000-0000-0000-000000000000    In my case returning that value as the result of an invalid ToGuid conversion was not a problem

User · Answer

A GUID is a 16-byte  128-bit  number  typically represented by a 32-character hexadecimal string   A GUID  in hex form  need not contain any alpha characters  though by chance it probably would   If you are targeting a GUID in hex form  you can check that the string is 32-characters long  after stripping dashes and curly brackets  and has only letters A-F and numbers   There is certain style of presenting GUIDs  dash-placement  and regular expressions can be used to check for this  e g           0 1   0-9a-fA-F   8 -  0-9a-fA-F   4 -  0-9a-fA-F   4 -  0-9a-fA-F   4 -  0-9a-fA-F   12    0 1       from http   www geekzilla co uk view8AD536EF-BC0D-427F-9F15-3A1BC663848E htm   That said  it should be emphasized that the GUID really is a 128-bit number and could be represented in a number of different ways

User · Answer

see http   en wikipedia org wiki Globally unique identifier  There is no guarantee that an alpha will actually be there

User · Answer

if MyGuid  Guild Empty                 Valid Guild             else             Invalid Guild

User · Answer

See if these helps  -  Guid Parse - Docs  Guid guidResult   Guid Parse inputString    Guid TryParse - Docs  bool isValid   Guid TryParse inputString  out guidOutput

[c#] How to validate GUID is a GUID

Examples related to c#

Examples related to asp.net

Examples related to string

Examples related to guid